August 16, 2011

Drilling underway at Tongo Project in Sierra Leone

16 August 2011

AIM: STEL

Stellar Diamonds plc

(“Stellar” or the “Company”)

Drilling underway at Tongo Project in Sierra Leone

Stellar Diamonds plc, the London listed (AIM: STEL) diamond mining and exploration company focused on West Africa announces the commencement of resource drilling at the Company’s high-grade Tongo kimberlite diamond project in eastern Sierra Leone.

Highlights:

  • Commencement of 6,000m diamond core drilling programme
  • Objective is to define a maiden inferred resource estimate to at least 200m below surface
  • Bulk sampling yielded 926 carats for undiluted grade of 115 carats per hundred tonnes (‘cpht’)
  • Potential in-situ kimberlite value of up to $220 per tonne

Chief Executive Karl Smithson commented:

“With the recent appointment of CAE Mining and the commencement of drilling we remain on track to establish our maiden resource at the Tongo Dyke project in the first quarter of 2012. The bulk sampling grades continue to prove encouraging, with the kimberlite yielding an average grade to date of 115cpht. A further diamond parcel of approximately 300 carats will be exported in the near future to combine with the parcel of 639cts already in Antwerp which was recently valued at $191 per carat. We remain confident on the potential that the Tongo kimberlite project offers and we look forward to updating the market on the progress we make as we work to establish a maiden resource base at both our Tongo and Droujba projects.”

Resource Drilling

Stellar recently signed a 6,000m core drilling contract with E-Global Drilling, with an option to extend the meterage if necessary. This first phase of drilling will be focussed on the 2.5km strike length of Tongo Dyke 1 in order to establish lateral and depth continuity of the kimberlite ore body at every 100m along strike. Holes are being planned to intersect the kimberlite at depths of 50m, 100m and 200m from surface, with some holes targeting intersections at 300m vertical depth.

In addition, the 1km long Tongo Dyke 4, located 1km to the north of Dyke 1 will also be drilled as part of the programme. Previous mini-bulk sampling of Dyke 4 undertaken by the Company returned grades of 100cpht.

CAE Mining are overseeing the resource drilling and bulk sampling programmes as part of their mandate to independently establish a maiden inferred resource estimate for the Tongo project.

Bulk Sampling and Processing Results

Bulk sampling of the 2.5km Dyke 1 kimberlite continues to yield high grades. Processing of some 1,360 tonnes of kimberlite and wall rock granite mix to date has yielded 926.30 carats for a diluted grade of 68cpht and an undiluted grade of 114.92cpht based on the 806 tonnes of kimberlite processed.

The diamond quality remains high and a second parcel will be exported in the near future and added to the 639 carats currently in stock in Antwerp that were recently valued at $191 per carat. The combined parcel will be sold in September to ascertain the current market price for the Tongo goods. The average grade of 115cpht and the previously received diamond value of $191 per carat give a potential current in-situ undiluted value of the Dyke 1 kimberlite of $220 per tonne.

The following table shows the cumulative results of the Tongo Dyke bulk sampling and processing programme as at 16 August 2011 and as at 11 July 2011:-

Cumulative to 11 July

2011

Cumulative to 16 August

2011

Kimberlite and granite processed (tonnes)

1,091

1,360

Kimberlite processed (tonnes)

687

806

Carats

752

926

Undiluted in situ grade (cpht)

109.5

114.92

Diluted grade (cpht)

68.93

68.11

Potential in situ undiluted value (per tonne)

$209

$220

About Stellar Diamonds plc

Stellar is a London (AIM: STEL) listed diamond mining and exploration company focussed on West Africa. Stellar owns a 100% interest in four high-grade kimberlite projects. In Guinea resource definition drilling is continuing on the diamondiferous Droujba kimberlite pipe and a processing plant is being established on site to process bulk samples. In Sierra Leone at Tongo a bulk sampling programme is ongoing on the high grade Dyke 1 and drilling has commenced on the kimberlite as part of the resource definition programme.

For further information please contact the following or visit the Company’s website at www.stellar-diamonds.com.

Stellar Diamonds plc

Karl Smithson,Chief ExecutiveTel: +44 (0) 20 7257 2930

Northland Capital Partners Limited

Gavin Burnell, Edward Hutton

Charles Vaughan (Sales) Tel: +44 (0) 20 7796 8800

Daniel Stewart & Company plc

Martin Lampshire, Oliver Rigby Tel: +44 (0) 20 7776 6550

Pelham Bell Pottinger

Charles Vivian / James MacFarlane Tel: +44 (0) 20 7861 3232